Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/10—Dispersions; Emulsions
  • A61K9/127—Synthetic bilayered vehicles, e.g. liposomes or liposomes with cholesterol as the only non-phosphatidyl surfactant
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
  • Y10T428/2984—Microcapsule with fluid core [includes liposome]

Definitions

• the present invention relates to an aqueous dispersion containing liposomes. More specifically, the present invention relates to an aqueous dispersion containing liposomes containing a hydroxy acid and an amino acid as stabilizing agents.
• Liposomes are vesicles composed of lipid bilayer membranes and their applications have recently been developed in various fields such as drug delivery systems, diagnostic drugs, artificial enzyme carriers, sensors and cosmetics.
• liposomes encapsulating drugs have been actively developed for the purposes of stabilization of unstable drugs, slow release of drugs in living bodies and targeting of drugs to lesion sites.
• liposomes themselves are often unstable to heat and it has been known that, even though they are prepared as a suspension, they relatively rapidly exhibit aggregation or fusion with one another as well as precipitation and coloration. Thus, these problems have been great problems of the commercialization of liposome formulations.
• Japanese Patent Application Laid-Open (KOKAI) No. 62-42733 discloses that liposomes were prepared by using dipalmitoylphosphatidylcholine, a synthetic phospholipid, as a lipid for forming liposomes and specific hydrating agents and sterilized by heat and these liposomes were stable without change of color after one year storage at room temperature.
• the stabilizing effect of the hydrating agents on liposomes prepared by using yolk lecithin or soybean lecithin was not described or suggested at all.
• the liposomes composed of synthetic phospholipids have a problem from an economical point of view since they are very expensive even though they are more stable than those composed of natural phospholipids.
• the present inventors have diligently studied to obtain an aqueous dispersion containing liposomes which shows good storage stability by using natural phospholipids which are inexpensive and have high safety as lipids for forming liposomes.
• the change of color of liposomes when they are stored in the form of an aqueous dispersion, can be prevented by adding a hydroxy acid and an amino acid to the aqueous dispersions containing liposomes composed of natural phospholipids and containing no drugs.
• the same effect can be attained as to the aqueous dispersions containing liposomes containing drugs and completed the present invention.
• an aqueous dispersion containing liposomes comprising yolk lecithin and/or soybean lecithin as lipids for forming liposomes, which dispersion contains one or more hydroxy acids and one or more amino acids.
• lipid for forming liposomes there can be mentioned those comprising yolk lecithin and/or soybean lecithin. So long as the lipids have a composition comprising the above lecithins, any lipids can be used for the present invention. That is, the advantages of the present invention can also be obtained by using the above lecithins mixed with the above lecithins in a hydrogenated form, synthetic phospholipids such as dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine, distearoylphosphatidylcholine, dicetylphosphate and phosphatidylglycerol.
• synthetic phospholipids such as dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine, distearoylphosphatidylcholine, dicetylphosphate and phosphatidylglycerol.
• these lipids for forming liposomes are normally used in an amount of from 0.0001 to 0.1 parts by weight, preferably from 0.001 to 0.05 parts by weight based on a part by weight of water.
• a membrane-forming adjuvant may be added to these lipids for forming liposomes, if desired.
• sterols such as cholesterol, aliphatic amines and fatty acids such as stearylamine and oleic acid can be exemplified.
• the amount of these membrane-forming adjuvants is not particularly limited and is normally from 0.05 to 0.5 parts by weight for the sterols and from 0.05 to 0.2 parts by weight for the aliphatic amines and fatty acids based on a part by weight of the lipids for forming liposomes.
• the hydroxy acid used for the present invention is not particularly limited, but one or more of members selected from lactic acid, tartaric acid, malic acid, citric acid and pharmaceutically acceptable salts thereof are preferably used. Among these hydroxy acids, citric acid and its pharmaceutically acceptable salts are particularly preferred.
• the amino acid is not also particularly limited, but one or more of members selected from glycine, alanine, leucine, serine, histidine, proline, hydroxyproline, cysteine, methionine, lysine, arginine, glutamic acid, aspartic acid and pharmaceutically acceptable salts thereof are preferably used.
• members selected from glycine, alanine, leucine, serine, histidine, proline, hydroxyproline, cysteine, methionine, lysine, arginine, glutamic acid, aspartic acid and pharmaceutically acceptable salts thereof are particularly preferred.
• the essential characteristics of the present invention reside in the use of at least one of the above hydroxy acids and at least one of the above amino acids in combination. Therefore, several kinds of the above hydroxy acids and several kinds of the above amino acids may be used in combination, and it is not intended to exclude using mixtures of more than two kinds of the compounds.
• concentration ranges of the hydroxy acids and the amino acids where the advantages can be obtained may be somewhat varied depending on the kinds of the hydroxy acid and the amino acid used in combination.
• sodium citrate and methionine when sodium citrate and methionine are used, from 0.05 to 5 parts by weight of sodium citrate (in terms of citric acid) and from 0.008 to 0.8 parts by weight of methionine can be suitably used with a part by weight of lipids for forming liposomes.
• sodium citrate and histidine hydrochloride When sodium citrate and histidine hydrochloride are used, from 0.05 to 5 parts by weight of sodium citrate (in terms of citric acid) and from 0.0006 to 0.3 parts by Weight of histidine hydrochloride (in terms of histidine) can be suitably used with a part by weight of lipids for forming liposomes.
• sodium citrate and arginine When sodium citrate and arginine are used, from 0.05 to 5 parts by weight of sodium citrate (in terms of citric acid) and from 0.02 to 4 parts by weight of arginine can be suitably used with a part by weight of lipids for forming liposomes.
• sodium citrate and sodium glutamate or sodium aspartate are used, from 0.05 to 5 parts by weight of sodium citrate (in terms of citric acid) and from 0.015 to 3 parts by weight of sodium glutamate or sodium aspartate (in terms of glutamic acid or aspartic acid) can be suitably used with a part by weight of lipids for forming liposomes.
• the advantages of the present invention can be attained by using a hydroxy acid and an amino acid in combination in amounts within the above proportion with respect to lipids for forming liposomes.
• the amount of the these stabilizing agents in an aqueous dispersion containing liposomes is greater than a certain amount, the operability of the dispersion will be declined because of the increase of viscosity of the dispersion and phase separation will be occurred because of floating of liposomes and they are not preferred.
• the amount of the amino acid exceeds a certain amount, decrease of the stabilizing effect is observed.
• a part by weight of an aqueous dispersion containing liposomes it is normally preferred that not more than 0.13 parts by weight of the hydroxy acid and, while the upper limit of the amount of the amino acid is varied depending on its kind, not more than 0.02 parts by weight of methionine, 0.015 parts by weight of histidine, 0.05 parts by weight of arginine or 0.08 parts by weight of glutamic acid or aspartic acid are used.
• the drugs to be contained in the liposomes of the present invention are not particularly limited and may be either hydrophilic or lipophilic.
• they may be agents affecting central nervous system, agents affecting peripheral nervous system, cardiovascular agents, agents affecting respiratory organs, agents affecting digestive organs, hormone preparations, vitamin preparations, agents related to blood and body fluids, agents affecting metabolism, carcinostatic agents, antiallergic agents, antibiotics preparations, chemotherapeutics, agents for ophthalmic use, diagnostic agents, analgesics and sedatives agents, physiologically active substances, prostaglandin agents, immunoregulatory drugs, anti-inflammatory agents and the like. Examples of these agents are set forth below, but the present invention is not limited to them:
• agents affecting central nervous system such as:
• antiepileptics such as phenobarbital
• antipyretics such as pranoprofen and ketoprofen
• psychotropic agents such as amitriptyline and chlorpromazine
• agents affecting peripheral nervous system such as;
• a) local anesthetics such as lidocaine, benzocaine, tetracaine and dibucaine;
• antispasmodics such as atropine and afloqualone
• antihypertensives such as reserpine and hydralazine
• vasoconstrictors such as phenylephrine, naphazoline and methoxamine
• vasodilators such as diltiazem and nifedipine
• antihyperlipemnia agents such as clofibrate and pravastatin
• agents affecting respiratory organs such as:
• antitussives such as methylephedrine and ephedrine
• bronchodilators such as theophylline; and pharmaceutically acceptable salts thereof.
• agents affecting digestive organs such as:
• TAS antiulcer agents such as farnesol, geraniol and 2-N- ⁇ 3-[3-(1-piperidinomethyl)phenoxy]propyl ⁇ amino-5-amino-1,3,4-thiadiazole (hereinafter abbreviated as "TAS");
• TAS 2-N- ⁇ 3-[3-(1-piperidinomethyl)phenoxy]propyl ⁇ amino-5-amino-1,3,4-thiadiazole
• hormone preparations such as;
• adrenal hormone preparations such as betamethasone phosphate, dexamethasone phosphate, hydrocortisone, triamcinolone and prednisolone;
• hormone preparations such as insulin
• vitamin preparations such as vitamin A and preparations and vitamin C and preparations
• agents related to blood and body fluids such as:
• hemostatics such as carbazochrome, tranexamic acid
• agents affecting metabolism such as;
• agents for liver disease such as glycyrrhizic acid•DL-methionine;
• agents for diabetic complications such as epalrestat
• carcinostatic agents such as mitomycin, adriamycin, methotrexate, cisplatin, tegafur, vincristine and doxorubicin;
• antiallergic agents such as;
• antihistamines such as chlorpheniramine and diphenhydramine
• antiallergic agents such as cromoglicic acid, tranilast and ketotifen
• antibiotics preparations such as amphotericin B, gentamicin, erythromycin, tetracycline, chloramphenicol and colistin methanesulfonic acid;
• chemotherapeutics such as ofloxacin, norfloxacin and miconazole;
• agents for ophthalmic use such as;
• antiglaucoma drugs such as epinephrine, timolol and carteolol;
• anticataract drugs such as glutathione and pirenoxine
• miotics and preparations such as pilocarpine and carbachol
• diagnostic agents such as fluorescein
• analgesics and sedatives agents such as morphine and codeine
• physiologically active substances such as erythropoietin
• prostaglandin agents such as prostaglandin E 1 and prostaglandin A 1 ;
• immunoregulatory drug such as interferon, interleukin, muramyl dipeptide, muramyl tripeptide, penicillamine and ciclosporin;
• anti-inflammatory agents such as fluorometholone, glycyrrhizic acid and dicrofenac;
• salts of the hydroxy acids, the amino acids and the drugs used for the present invention sodium salts, potassium salts and the like can be mentioned for the hydroxy acids, glutamic acid, dicrofenac, betamethasone phosphate and the like, hydrochloride salts, sulfate salts and the like can be mentioned for arginine, histidine, gentamicin, morphine, lidocaine, pilocarpine and the like, and maleate salts and the like can be mentioned for chlorpheniramine and timolol.
• the process for preparing the aqueous dispersion containing liposomes of the present invention will be explained. Though various known methods are applicable, it can be prepared, for example, as follows.
• the lipids for forming liposomes comprising yolk lecitin and, if desired, cholesterol and the like as membrane-forming adjuvants are dissolved in a suitable solvent such as chloroform and the solvent is evaporated in vacuo to prepare a lipid film.
• This film is suspended in water, and a hydroxy acid and an amino acid are added to give an aqueous dispersion containing liposomes of the present invention.
• the lipid film prepared as above can be suspended in a solution containing a hydroxy acid and an amino acid to give an aqueous dispersion containing liposomes of the present invention.
• an aqueous dispersion containing liposomes encapsulating drugs according to the present invention can be prepared as follows.
• the drug is a hydrophilic drug
• the drug may be dissolved in water or a solution containing a hydroxy acid and an amino acid for supending the lipid film, and the liposomes may be prepared as the same manner as above.
• the drug when the drug is a lipophilic drug, the drug may be mixed in the organic solvent with lipids for forming liposomes and, if desired, membrane-forming adjuvants and the liposomes can be prepared as the same manner as above.
• encapsulation efficiency of drugs can be increased by repeating freeze-thawing process, or the size distribution of the liposomes can be controlled by the extrusion method (M. J. Hope, M. B. Bally, G. Webb and P. R. Cullis,: Biochim. Biophys. Acta 812, 55 (1985)) or the like.
• the drugs which are not encapsulated in the liposomes can be removed by gel filteration, centrifugal separation, affinity chromatography or the like.
• aqueous dispersion containing liposomes obtained as described above are expected in various applications and it may be used, for example, as cosmetics such as moisture-holding agents for skin care and as pharmaceutical preparations such as parenteral injections, eye drops, nasal drops, endermic agents, inhalation agents and oral agents
• aqueous dispersion containing liposomes of the present invention as formulations such as those described above, conventional additives such as isotonic agents, pH adjusting agents, antiseptic agents and stabilizing agents may be added so long as the advantages of the dispersion according to the present invention are not deteriorated.
• the aqueous dispersion containing liposomes of the present invention may be subjected to a sterilizing treatment by a fractional sterilization method. The stability of the dispersion is not decreased by this treatment.
• nitrogen gas substitution is generally employed when a liquid preparation is filled in ampouls and the like. Though the aqueous dispersion containing liposomes of the present invention is stable without the nitrogen gas substitution, a greater stability can be expected by employing such nitrogen gas substitution.
• L 1 , a 1 and b 1 are the measured values obtained for a sample before storage and L 2 , a 2 and b 2 are for a sample after storage.
• the total drug concentration is obtained as follows. First, a drug concentration of liquid obtained by treating an aqueous dispersion containing liposomes with Triton X-100 to destroy liposomes contained in the dispersion is determined. Then, the total drug concentration is calculated from the above-obtained drug concentration of the liquid so that the total drug concentration expresses the drug concentration in the original dispersion. Further, the "encapsulation efficiency" was obtained in accordance with the following equation: ##EQU2##
• total drug concentration has the same meaning as above and the term “unencapsulated drug concentration” is determined as a drug concentration in a filtrate obtained from ultrafiltration of an aqueous dispersion for removing the liposomes.
• a milk white liposome stock dispersion of which liposomes contained soybean lecithin (phosphatidylcholine) was obtained in a manner similar to the above by using soybean lecithin (PC purity: 97.3%, Nihon Seika Col,Ltd.) instead of the egg phosphatidylcholine.
• soybean lecithin PC purity: 97.3%, Nihon Seika Col,Ltd.
• aqueous dispersions containing liposomes of the present invention To one part by volume of the obtained liposome stock dispersions, one part by volume of a solution containing a hydroxy acid and one or more amino acids selected from various hydroxy acids and amino acids was added to obtain aqueous dispersions containing liposomes of the present invention. For comparison, to one part by volume of the above liposome stock dispersions, one part by volume of phosphate buffer containing a hydroxy acid or an amino acid alone, or one part by volume of phosphate buffer containing no stabilizing agents was added to give comparative aqueous dispersions containing liposomes.
• aqueous dispersions containing liposomes of which concentrations of the stabilizing agents are shown in Table 2.
• lipids for forming liposomes shown in Table 3 were dissolved in a chloroform/methanol mixture (10:1) and the solvent was removed by an evaporator to form lipid films having various compositions.
• aqueous dispersions containing liposomes One part by volume of a solution containing 4% of sodium citrate and 0.4% of sodium glutamate was added to one part by volume of the liposome stock dispersions obtained above to give aqueous dispersions containing liposomes according to the present invention.
• one part by volume of the Britton-Robinson buffer was added to one part by volume of each of the above liposome stock dispersions to give comparative aqueous dispersions containing liposomes.
• phosphate buffer made isotonic with sodium chloride
• pH 8.3 5 ml of phosphate buffer (made isotonic with sodium chloride) of pH 8.3 was added to the lipid film prepared in Example 1 containing egg phosphatidylcholine and strongly vortexed, and the obtained liquid was extruded under pressure through a polycarbonate membrane filter having a pore size of 0.2 ⁇ m (NUCLEPORE®: available from Nomura Microscience Co.,Ltd.) to give a milk white liposome stock dispersion.
• NUCLEPORE® available from Nomura Microscience Co.,Ltd.
• aqueous dispersion containing liposomes according to the present invention where the outside aqueous phase of the liposomes contained the stabilizing agents.
• phosphate buffer made isotonic with sodium chloride
• pH 8.3 containing 0.2% of sodium citrate and 0.2% of methionine
• a polycarbonate membrane filter having a pore size of 0.2 ⁇ m (NUCLEPORE®: available from Nomura Microscience Co.,Ltd.) to give an aqueous dispersion containing liposomes of the present invention where the inside and outside aqueous phases of the liposomes contained the stabilizing agents.
• phosphate buffer containing no stabilizing agents was added to one part of the above liposome stock dispersion to give a comparative aqueous dispersion containing liposomes.
• the above-obtained aqueous dispersion containing liposomes according to the present invention where the inside and outside aqueous phases of the liposomes contained the stabilizing agents was centrifuged at 100,000 ⁇ g and the precipitated liposomes were dispersed again in the phosphate buffer to give a comparative aqueous dispersion containing liposomes where only the inside aqueous phases of the liposomes contained the stabilizing agents.
• phosphate buffer made isotonic with sodium chloride
• pH 8.3 containing 0.4% of sodium betamethasone phosphate
• This aqueous dispersion containing liposomes was frozen with dry ice/acetone and thawed in a water bath at 20° C. After repeating this freeze-thawing process eight times, the dispersion was extruded under pressure through a polycarbonate membrane filter having a pore size of 0.2 ⁇ m (NUCLEPORE ®: available from Nomura Microscience Co.,Ltd.).
• this aqueous dispersion containing liposomes was centrifuged at 100,000 ⁇ g to remove unencapsulated drug and was dispersing again the precipitated liposomes in phosphate buffer to give a liposome stock dispersion containing sodium betamethasone phosphate.
• aqueous dispersions containing liposomes according to the present invention having concentrations of the lipid for forming liposomes of 0.04 and 0.025 parts by weight (based on a part by weight of the buffer where the lipid was dispersed).
• the above liposome stock dispersion was diluted with phosphate buffer by five times or fifty times, and one part by volume of phosphate buffer containing 0.04% of sodium citrate and 0.02% of sodium aspartate or one part by volume of phosphate buffer containing 0.004% of sodium citrate and 0.002% of sodium aspartate was added to one part by volume of the diluted dispersions to give aqueous dispersions containing liposomes according to the present invention having a concentration of the lipid for forming liposomes of 0.0025 or 0.00025 parts by weight.
• a dispersion was prepared in a manner similar to the above except that sodium citrate and sodium aspartate were not added.
• the aqueous dispersion containing liposomes of the present invention hardly exhibited change of appearance and the relative encapsulation efficiency was more than about 90% at all of the concentrations of the lipid for forming liposomes. Therefore, it was found that the aqueous dispersions containing liposomes of the present invention were stable regardless of the concentration of the lipid for forming liposomes.
• aqueous dispersions containing liposomes of the present invention To one part by volume of the liposome stock dispersion prepared in Example 6 containing sodium betamethasone phosphate, one part by volume of a solution containing sodium citrate and an amino acid selected from various amino acids was added to give aqueous dispersions containing liposomes of the present invention. For comparison, to one part by volume of the above liposome stock dispersion, one part by volume of phosphate buffer containing sodium citrate or an amino acid alone or phosphate buffer containing no stabilizing agents was added to give comparative aqueous dispersions containing liposomes.
• aqueous dispersion containing liposomes of the present invention To one part by volume of the liposome stock dispersion prepared in Example 6 containing sodium betamethasone phosphate, one part by volume of a solution containing 4% of sodium citrate and 0.4 % of sodium glutamate was added to give an aqueous dispersion containing liposomes of the present invention.
• a dispersion was prepared in a manner similar to the above except that sodium glutamate and sodium citrate were not added and nitrogen gas substitution was carried out when it was filled into ampoules.
• Example 6 In a manner similar to Example 6 except that 5 ml of phosphate buffer of pH 6.0 (made isotonic with sodium chloride) containing 0.5% of morphine hydrochloride was used instead of 5 ml of phosphate buffer of pH 8.3 containing 0.4% of sodium betamethasone phosphate in Example 6, a liposome stock dispersion was obtained.
• phosphate buffer containing 0.4% of sodium citrate and 0.4% of sodium glutamate was added to give an aqueous dispersion containing liposomes of the present invention.
• phosphate buffer containing 0.8% of sodium citrate or 0.8% of sodium glutamate alone or one part by volume of phosphate buffer containing no stabilizing agents was added to give comparative aqueous dispersions containing liposomes.
• aqueous dispersion containing liposomes of the present invention can prevent change of appearance and, moreover, can prevent the leak of drugs.
• Example 6 In a manner similar to Example 6 except that 5 ml of phosphate buffer of pH 8.3 containing 0.4% of sodium betamethasone phosphate in Example 6 was replaced with 5 ml of phosphate buffer of pH 8.3 containing 0.4% of sodium dexamethasone phosphate, a liposome stock dispersion containing sodium dexamethasone phosphate was obtained.
• Example 6 In a manner similar to Example 6 except that 5 ml of phosphate buffer of pH 8.3 containing 0.4% of sodium betamethasone phosphate in Example 6 was replaced with 5 ml of phosphate buffer of pH 8.0 containing 5% of timolol maleate, a liposome stock dispersion containing timolol maleate was obtained.
• phosphate buffer made isotonic with sodium chloride
• pH 8.0 pH 8.0 containing 0.2% of sodium dicrofenac
• aqueous dispersion containing liposomes was extruded under pressure through a polycarbonate membrane filter having a pore size of 0.2 ⁇ m (NUCLEPORE®: available from Nomura Microscience Co.,Ltd.) to give a liposome stock dispersion containing sodium dicrofenac.
• phosphate buffer made isotonic with sodium chloride
• pH 8.0 pH 8.0
• phosphate buffer made isotonic with sodium chloride
• pH 8.0 pH 8.0
• aqueous dispersion containing liposomes was extruded under pressure through a polycarbonate membrane filter having a pore size of 0.2 ⁇ m (NUCLEPORE®: available from Nomura Microscience Co.,Ltd.) to give a liposome stock dispersion containing fluorometholone.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of phosphate buffer of pH 7.0 containing 0.1% of sodium pranoprofen, a liposome stock dispersion containing sodium pranoprofen was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 9.0 containing 4% of tegafur, a liposome stock dispersion containing tegafur was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 6.0 containing 0.3% of gentamicin sulfate, a liposome stock dispersion containing gentamicin sulfate was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 5.0 containing 0.5% of chlorpheniramine maleate, a liposome stock dispersion containing chlorpheniramine maleate was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 5.5 containing 2% of sodium cromoglicate, a liposome stock dispersion containing sodium cromoglicate was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 7.0 containing 12,000 units/ml of urokinase, a liposome stock dispersion containing urokinase was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 6.0 containing 1% of lidocaine hydrochloride, a liposome stock dispersion containing lidocaine hydrochloride was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 5.0 containing 0.5% of phenylephrine hydrochloride, a liposome stock dispersion containing phenylephrine hydrochloride was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 5.0 containing 1% of pilocarpine hydrochloride, a liposome stock dispersion containing pilocarpine hydrochloride was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 7.0 containing 0.75% of carbachol, a liposome stock dispersion containing carbachol was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 5.0 containing 0.2% of TAS, a liposome stock dispersion containing TAS was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 5.0 containing 0.5% of tropicamide, a liposome stock dispersion containing tropicamide was obtained.
• Example 12 In a manner similar to Example 12 except that 5 ml of phosphate buffer of pH 8.0 containing 0.2% of sodium dicrofenac in Example 12 was replaced with 5 ml of Britton-Robinson buffer of pH 6.0 containing 2% of glutathione, a liposome stock dispersion containing glutathione was obtained.
• Example 2 To the lipid film prepared in Example 1 containing egg phosphatidylcholine, 5 ml of Britton-Robinson buffer of pH 5.0 containing 1% of penicllamine was added and strongly vortexed. The obtained aqueous dispersion containing liposomes was extruded under pressure through a polycarbonate membrane filter having a pore size of 0.2 ⁇ m (NUCLEPORE®: available from Nomura Microscience Co.,Ltd.) and centrifuged at 100,000 ⁇ g to remove unencapsulated drug and was dispersing again the precipitated liposomes in Brutton-Robinson buffer to give a liposome stock dispersion containing penicillamine.
• NUCLEPORE® available from Nomura Microscience Co.,Ltd.
• aqueous dispersion containing liposomes obtained in Example 8 containing 2% of sodium citrate and 0.2% of sodium glutamate, of which liposomes encapsulated betamethasone phosphate was diluted with phosphate buffer (pH 8.3) containing 2% of sodium citrate and 0.2% of sodium glutamate to give an aqueous dispersion containing liposomes, which contained 1 mg of betamethasone per 1 ml.
• the dispersion was filled into 2 ml of glass ampoules and sterilized by heating at 70° C. for 1 hour three times every 24 hours to give a parenteral injection.
• aqueous dispersion containing liposomes obtained in Example 8 containing 2% of sodium citrate and 0.2% of sodium glutamate, of which liposomes encapsulated betamethasone phosphate was diluted with phosphate buffer (pH 8.3) containing 2% of sodium citrate and 0.2% of sodium glutamate and, further, added with benzalkonium chloride of which final concentration in the dispersion was 0.005% to give an aqueous dispersion containing 1 mg of betamethasone per 1 ml. This dispersion was filtered through a membrane filter of 0.22 ⁇ m and filled in a container for spraying as a nasal drop.
• aqueous dispersion containing liposomes obtained in Example 8 containing 2% of sodium citrate and 0.2% of sodium glutamate, of which liposomes encapsulated betamethasone phosphate was diluted with phosphate buffer (pH 8.3) containing 2% of sodium citrate and 0.2% of sodium glutamate and, further, added with benzalkonium chloride of which final concentration in the dispersion was 0.005% to give an aqueous dispersion containing 1 mg of betamethasone per 1 ml.
• This dispersion was filtered through a membrane filter of 0.22 ⁇ m and filled in a plastic container with sponge as an endermic agent.
• aqueous dispersion containing liposomes obtained in Example 8 containing 2% of sodium citrate and 0.2% of sodium glutamate, of which liposomes encapsulated betamethasone phosphate was diluted with phosphate buffer (pH 8.3) containing 2% of sodium citrate and 0.2% of sodium glutamate and, further, added with benzalkonium chloride of which final concentration in the dispersion was 0.005% to give an aqueous dispersion containing 1 mg of betamethasone per 1 ml.
• This dispersion was filtered through a membrane filter of 0.22 ⁇ m and filled in a nebulizer container as an inhalation agent.
• aqueous dispersion containing liposomes obtained in Example 8 containing 2% of sodium citrate and 0.2% of sodium glutamate, of which liposomes encapsulated betamethasone phosphate was diluted with phosphate buffer (pH 8.3) containing 2% of sodium citrate and 0.2% of sodium glutamate and, further, added with D-sorbitol and potassium sorbate of which final concentrations in the dispersion were 10% and 0.1% respectively to give an aqueous dispersion containing 1 mg of betamethasone per 1 ml. This dispersion was filtered through a membrane filter of 0.45 ⁇ m and filled in a glass container as an oral agent.
• aqueous dispersion containing liposomes obtained in Example 9 containing 0.2% of sodium citrate and 0.2% of sodium glutamate, of which liposomes encapsulated morphine hydrochloride, was diluted with phosphate buffer (pH 6.0) containing 0.2% of sodium citrate and 0.2% of sodium glutamate to give an aqueous dispersion containing 0.5 mg of morphine hydrochloride per 1 ml.
• This dispersion was filtered through a membrane filter of 0.22 ⁇ m and filled in a glass ampoule as a paranteral injection.
• aqueous dispersion containing liposomes obtained in Example 11 containing 0.5% of sodium citrate and 0.5% of sodium glutamate, of which liposomes encapsulated timolol maleate was diluted with phosphate buffer (pH 8.0) containing 0.5% of sodium citrate and 0.5% of sodium glutamate and, further, added with benzalkonium chloride of which final concentration in the dispersion was 0.005% to give an aqueous dispersion containing 2.5 mg of timolol per 1 ml. This dispersion was filtered through a membrane filter of 0.22 ⁇ m and filled in a 5-ml eye drop bottle as an eye drop.
• phosphate buffer pH 8.0
• phosphate buffer pH 8.0
• aqueous dispersions containing liposomes which hardly show coloration though they are composed of natural phospholipids, which are inexpensive and safe, show little leak of drugs encapsulated therein and hence are excellent in storage stability.

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• 1994
  • 1994-03-29 CA CA002120197A patent/CA2120197A1/en not_active Abandoned
  • 1994-03-31 DE DE69425773T patent/DE69425773T2/de not_active Expired - Fee Related
  • 1994-03-31 EP EP94105146A patent/EP0622072B1/de not_active Expired - Lifetime
• 1995
  • 1995-05-24 US US08/448,972 patent/US5569464A/en not_active Expired - Fee Related

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